Acupuncture is one of the oldest forms of medical practice and has been used in China for thousands of years. The general theory is that the body has energy in the form of "Qi" (chee) and "blood" which extends through the body organs and appears, in lines and points, on the skin. Each active point (site) on the skin is called an "acupuncture point" ("men" or "gates") and is very small, in the order of one square millimeter.
After the proper acupuncture points are located, the patient may be treated using those points. The traditional Chinese treatment is to inject needles (thin, solid, stainless-steel needles), at various depths, through the acupuncture points. More recently, various practitioners have also used laser beam (light), pressure (massage) and electrical stimulation applied to the selected acupuncture points.
A skilled acupuncturist, who may have been trained for years, is able to find the acupuncture points by feeling with his/her fingers. The acupuncture points, in various versions, have been published in charts and in written descriptions, However, due to individual differences, such as differences in the size and shape of patients, even experienced acupuncture practitioners who rely on "body units" (width of the second joint of the thumb), may have difficulty correctly locating the acupuncture points. In addition, the location of those points may be time-consuming and acupuncturists, to avoid embarrassment and delay, may use points which are close to the accepted acupuncture points, but are not exactly at those points.
The interest in methods used by eastern medicine, especially acupuncture, is growing rapidly in the west. Some patients believe that methods employed by eastern medicine are simpler and may in some cases lead to better results, compared to traditional western methods of diagnostics and healing. Successful eastern healers often have enormous experience and knowledge and acquired their skills in strict training and years of practicing.
In recent years, it has been shown, in the patent literature and elsewhere, that traditional eastern methods can be modified using electronic devices to reach results faster without the loss of effectiveness. Modern electronics can make eastern acupuncture methods more accessible to the western medical community.
The basis for eastern methods is acupuncture diagnosis which in turn stems from correct determination of the activity in individual acupuncture points. Without such diagnosis the treatment is aimless and less effective, regardless which treatment method is selected.
The traditional Chinese medicine identifies a large number of acupuncture points on the human body which differ slightly in their physical properties. FIG. 1 shows an example of acupuncture points on the left hand, the points being shown as small circles. By electronically measuring certain physical properties, one can obtain the same information as might be obtained by a highly skilled master of classical acupuncture, using classical methods. Hence, electronic measurement of acupuncture point activity can provide reproducible information with less extensive operator training in acupuncture.
By examining the electrical properties in acupuncture points, it is possible to determine the electrical point-to-point properties of electrical potential (voltage), resistance and impedance. However, measuring of electrical potential (voltage) requires a relatively complex apparatus, as common electromagnetic noise can cause significant errors. Measuring the d.c. resistance is influenced by the following: tissue polarization, electrochemical potential found at the contact point of the electrode with the skin and the electro-conductivity of the skin. Because of these disturbing factors, the measured potential and resistance values are difficult to reproduce and measurement methods, based on d.c. resistance, must include complex procedures to compensate for the disturbing factors.
The measuring of impedance using alternating current (a.c.) is more precise. The acupuncture point is defined as a point on the skin with smallest impedance value relative to the immediate surroundings. Using a.c. impedance measurement, there is no tissue polarization and the electrochemical potentials because at the contact point they compensate each other. Moreover, since the impedance capacity component dominates (Z=R-j'Xc), the influence of resistance in the contact point is diminished and the measurements are more accurate. The problem remains to select the proper frequency of the measuring current and the measuring current's amplitude.
U.S. Pat. No. 4,016,870 ("Lock '870 patent"), entitled "Electronic Acupuncture Point Finder" states that the acupuncture points coincide with points of low body impedance. It discusses prior devices using an oscillator in which a tone changes as the finder probe passes over an acupuncture point. The Lock '870 patent discloses a battery operated "on-off" point finder probe and a hand-held "grabber" electrode. The impedance difference of points touched by the finder probe are compared with a set of fixed impedances (impedance bridge) to distinguish abnormal impedance points, by an imbalance signal. The points are indicated by an on-off ammeter, a pulse tone, and two lights. The impedance difference is used to find acupuncture points; but the points are not measured in ohms or analyzed.
U.S. Pat. No. 4,408,617 is entitled "Apparatus For Detecting The Acupuncture Points On A Patient And For Applying Electrical Stimulating Signals To the Detected Points" ("August '617 patent"). A generator (oscillator) delivers a sawtooth signal to the needle of a probe. The impedance difference is used to find acupuncture points; but the points are not measured in ohms or analyzed.